diff --git a/README.md b/README.md
index d9104b6..d77901a 100644
--- a/README.md
+++ b/README.md
@@ -103,6 +103,10 @@ dodo diff --min-duration-diff 200ms --original-sqls 'output/sql/*.sql' output/re
 
 # diff of two replay result directories
 dodo diff replay1/ replay2/
+
+
+# Export table data
+dodo export --help
 ```
 
 ### Config
diff --git a/cmd/create.go b/cmd/create.go
index d51ebc8..a420ae0 100644
--- a/cmd/create.go
+++ b/cmd/create.go
@@ -16,11 +16,10 @@ limitations under the License.
 package cmd
 
 import (
-	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 	"slices"
-	"strings"
 
 	"github.com/emirpasic/gods/queues/circularbuffer"
 	"github.com/samber/lo"
@@ -151,30 +150,13 @@ func completeCreateConfig() (err error) {
 			}
 		}
 		createTableDDLs = tableDDLs
-
-		return err
+		return nil
 	}
 
 	ddldir := filepath.Join(GlobalConfig.OutputDir, "ddl")
 
-	GlobalConfig.DBs, GlobalConfig.Tables = lo.Uniq(GlobalConfig.DBs), lo.Uniq(GlobalConfig.Tables)
-	dbs, tables := GlobalConfig.DBs, GlobalConfig.Tables
-	if len(dbs) == 0 && len(tables) == 0 {
-		return errors.New("expected at least one database or tables, please use --dbs/--tables flag or --ddl flag")
-	} else if len(dbs) == 1 {
-		// prepend default database if only one database specified
-		prefix := dbs[0] + "."
-		for i, t := range GlobalConfig.Tables {
-			if !strings.Contains(t, ".") {
-				GlobalConfig.Tables[i] = prefix + t
-			}
-		}
-	} else {
-		for _, t := range tables {
-			if !strings.Contains(t, ".") {
-				return errors.New("expected database in table name when zero/multiple databases specified, e.g. --tables db1.table1,db2.table2")
-			}
-		}
+	if err := completeDBTables(); err != nil {
+		return err
 	}
 
 	if len(GlobalConfig.Tables) == 0 {
@@ -198,6 +180,14 @@ func completeCreateConfig() (err error) {
 	} else {
 		for _, table := range GlobalConfig.Tables {
 			tableddl := filepath.Join(ddldir, fmt.Sprintf("%s.table.sql", table))
+			if _, err := os.Stat(tableddl); err != nil {
+				// maybe a view
+				fmatch := filepath.Join(ddldir, fmt.Sprintf("%s.*view.sql", table))
+				if viewddls, err := src.FileGlob([]string{fmatch}); err == nil && len(viewddls) > 0 {
+					createOtherDDLs = append(createOtherDDLs, viewddls...)
+				}
+				continue
+			}
 			createTableDDLs = append(createTableDDLs, tableddl)
 		}
 	}
diff --git a/cmd/dump.go b/cmd/dump.go
index 7f794f1..dc5d286 100644
--- a/cmd/dump.go
+++ b/cmd/dump.go
@@ -162,6 +162,10 @@ func init() {
 	pFlags.StringVar(&DumpConfig.SSHPrivateKey, "ssh-private-key", "~/.ssh/id_rsa", "File path of SSH private key for '--ssh-address'")
 	addAnonymizeBaseFlags(pFlags, false)
 
+	dumpCmd.RegisterFlagCompletionFunc("query-states", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		return []string{"ok", "eof", "err"}, cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault
+	})
+
 	flags := dumpCmd.Flags()
 	flags.BoolVar(&DumpConfig.Clean, "clean", false, "Clean previous data and output directory")
 }
diff --git a/cmd/export.go b/cmd/export.go
new file mode 100644
index 0000000..f19745d
--- /dev/null
+++ b/cmd/export.go
@@ -0,0 +1,201 @@
+/*
+Copyright © 2025 Thearas thearas850@gmail.com
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package cmd
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os/signal"
+	"strings"
+	"syscall"
+
+	"github.com/jmoiron/sqlx"
+	"github.com/samber/lo"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"github.com/valyala/fasttemplate"
+
+	"github.com/Thearas/dodo/src"
+)
+
+// ExportConfig holds the configuration values
+var ExportConfig = Export{}
+
+// Export holds the configuration for the export command
+type Export struct {
+	Target     string
+	ToURL      string
+	Properties map[string]string
+	With       map[string]string
+
+	dbconn *sqlx.DB
+}
+
+// TODO: Support BROKER export?
+// exportCmd represents the export command
+var exportCmd = &cobra.Command{
+	Use:   "export",
+	Short: "Export data from Doris",
+	Long: `Export data from Doris via [Export](https://doris.apache.org/docs/sql-manual/sql-statements/data-modification/load-and-export/EXPORT) command.
+
+Example:
+  dodo export --target s3 --url 's3://bucket/export/{db}/{table}_' -p timeout=60 -w s3.endpoint=xxx -w s3.access_key=xxx -w s3.secret_key=xxx
+  dodo export --target hdfs --url 'hdfs://path/to/export/{db}/{table}_' -w fs.defaultFS=hdfs://HDFS8000871 -w hadoop.username=xxx`,
+	Aliases: []string{"e"},
+	PersistentPreRunE: func(cmd *cobra.Command, _ []string) error {
+		return initConfig(cmd)
+	},
+	SilenceUsage: true,
+	RunE: func(cmd *cobra.Command, _ []string) (err error) {
+		ctx, _ := signal.NotifyContext(cmd.Context(), syscall.SIGABRT, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+
+		if err := completeExportConfig(ctx); err != nil {
+			return err
+		}
+		GlobalConfig.Parallel = min(GlobalConfig.Parallel, len(GlobalConfig.Tables))
+
+		logrus.Infof("Export data for %d table(s) to '%s', parallel: %d\n", len(GlobalConfig.Tables), ExportConfig.ToURL, GlobalConfig.Parallel)
+		if len(GlobalConfig.Tables) == 0 {
+			return nil
+		}
+		if !src.Confirm("Confirm") {
+			return nil
+		}
+
+		g := src.ParallelGroup(GlobalConfig.Parallel)
+		for _, t := range GlobalConfig.Tables {
+			dbtable := strings.SplitN(t, ".", 2)
+			if len(dbtable) != 2 {
+				return fmt.Errorf("invalid table format '%s', expected 'db.table'", t)
+			}
+			dbname, table := dbtable[0], dbtable[1]
+			toURL := fasttemplate.ExecuteString(ExportConfig.ToURL, "{", "}", map[string]any{"db": dbname, "table": table})
+
+			g.Go(func() error {
+				logrus.Infof("Exporting table '%s.%s' to '%s'", dbname, table, toURL)
+				if err := src.Export(ctx, ExportConfig.dbconn, dbname, table, ExportConfig.Target, toURL, ExportConfig.With, ExportConfig.Properties); err != nil {
+					return fmt.Errorf("export table '%s.%s' failed: %w", dbname, table, err)
+				}
+				logrus.Infof("Export completed for table '%s.%s'", dbname, table)
+				return nil
+			})
+		}
+
+		return g.Wait()
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(exportCmd)
+	exportCmd.PersistentFlags().SortFlags = false
+	exportCmd.Flags().SortFlags = false
+
+	pFlags := exportCmd.PersistentFlags()
+	pFlags.StringVarP(&ExportConfig.Target, "target", "t", "s3", "Target storage for the export, e.g. 's3', 'hdfs'")
+	pFlags.StringVarP(&ExportConfig.ToURL, "url", "u", "", "Target URL that Doris export to, can use placeholders {db} and {table}, e.g. 's3://bucket/export/{db}/{table}_', 'hdfs://path/to/{db}/{table}_'")
+	pFlags.StringToStringVarP(&ExportConfig.Properties, "props", "p", map[string]string{}, "Additional properties, e.g. 'format=parquet'")
+	pFlags.StringToStringVarP(&ExportConfig.With, "with", "w", map[string]string{}, "Additional options for export target, e.g. 's3.endpoint=xxx'")
+
+	exportCmd.RegisterFlagCompletionFunc("target", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		return []string{"s3", "hdfs", "local"}, cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault
+	})
+
+	exportCmd.RegisterFlagCompletionFunc("url", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		compopts := cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault
+		switch ExportConfig.Target {
+		case "s3":
+			return []string{"s3://"}, compopts
+		case "hdfs":
+			return []string{"hdfs://"}, compopts
+		case "local":
+			return []string{"file://"}, compopts
+		}
+		return []string{}, cobra.ShellCompDirectiveError
+	})
+
+	compopts := cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault | cobra.ShellCompDirectiveNoSpace | cobra.ShellCompDirectiveKeepOrder
+	exportCmd.RegisterFlagCompletionFunc("props", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		// https://doris.apache.org/docs/sql-manual/sql-statements/data-modification/load-and-export/EXPORT#optional-parameters
+		return []string{
+				"label=",
+				"column_separator=",
+				"line_delimiter=",
+				"timeout=",
+				"columns=",
+				"format=",
+				"parallelism=",
+				"delete_existing_files=",
+				"max_file_size=",
+				"with_bom=",
+				"compress_type=",
+			},
+			compopts
+	})
+
+	exportCmd.RegisterFlagCompletionFunc("with", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		switch ExportConfig.Target {
+		case "s3":
+			return []string{"s3.endpoint=", "s3.access_key=", "s3.secret_key=", "s3.region="}, compopts
+		case "hdfs":
+			return []string{"fs.defaultFS=", "hadoop.username=", "fs.", "dfs.", "hadoop."}, compopts
+		}
+		return []string{}, cobra.ShellCompDirectiveError
+	})
+}
+
+func completeExportConfig(ctx context.Context) (err error) {
+	if err = completeDBTables(); err != nil {
+		return err
+	}
+
+	ExportConfig.Target = strings.ToLower(ExportConfig.Target)
+	if ExportConfig.Target == "" {
+		return errors.New("export target is required, use --target or -t to specify it")
+	}
+	urlPrefix := ExportConfig.Target
+	if urlPrefix == "local" {
+		urlPrefix = "file"
+	}
+	if !strings.HasPrefix(ExportConfig.ToURL, urlPrefix+"://") {
+		return fmt.Errorf("export URL must start with '%s://', got: '%s'", urlPrefix, ExportConfig.ToURL)
+	}
+
+	ExportConfig.dbconn, err = connectDBWithoutDBName()
+	if err != nil {
+		return fmt.Errorf("failed to connect to database: %w", err)
+	}
+
+	// find tables if not provided
+	if len(GlobalConfig.Tables) > 0 {
+		return nil
+	}
+	for _, db := range GlobalConfig.DBs {
+		schemas, err := src.ShowTables(ctx, ExportConfig.dbconn, db)
+		if err != nil {
+			return fmt.Errorf("failed to get tables for database '%s': %w", db, err)
+		}
+		tables := lo.FilterMap(schemas, func(s *src.Schema, _ int) (string, bool) {
+			return s.Name, s.Type == src.SchemaTypeTable
+		})
+		logrus.Infof("Found %d table(s) in database '%s'", len(tables), db)
+		for _, table := range tables {
+			GlobalConfig.Tables = append(GlobalConfig.Tables, db+"."+table)
+		}
+	}
+
+	return nil
+}
diff --git a/cmd/gendata.go b/cmd/gendata.go
index 9a62172..fab06db 100644
--- a/cmd/gendata.go
+++ b/cmd/gendata.go
@@ -268,6 +268,10 @@ func init() {
 	pFlags.StringVarP(&GendataConfig.Query, "query", "q", "", "SQL query file to generate data, only can be used when LLM is on")
 	pFlags.StringVarP(&GendataConfig.Prompt, "prompt", "p", "", "Additional user prompt for LLM")
 	addAnonymizeBaseFlags(pFlags, false)
+
+	gendataCmd.RegisterFlagCompletionFunc("llm", func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
+		return []string{"deepseek-reasoner", "deepseek-chat"}, cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault
+	})
 }
 
 // completeGendataConfig validates and completes the gendata configuration
@@ -299,24 +303,8 @@ func completeGendataConfig() (err error) {
 		return nil
 	}
 
-	GlobalConfig.DBs, GlobalConfig.Tables = lo.Uniq(GlobalConfig.DBs), lo.Uniq(GlobalConfig.Tables)
-	dbs, tables := GlobalConfig.DBs, GlobalConfig.Tables
-	if len(dbs) == 0 && len(tables) == 0 {
-		return errors.New("expected at least one database or tables, please use --dbs/--tables flag or --ddl flag with '.sql' file(s)")
-	} else if len(dbs) == 1 {
-		// prepend default database if only one database specified
-		prefix := dbs[0] + "."
-		for i, t := range GlobalConfig.Tables {
-			if !strings.Contains(t, ".") {
-				GlobalConfig.Tables[i] = prefix + t
-			}
-		}
-	} else {
-		for _, t := range tables {
-			if !strings.Contains(t, ".") {
-				return errors.New("expected database in table name when zero/multiple databases specified, e.g. --tables db1.table1,db2.table2")
-			}
-		}
+	if err := completeDBTables(); err != nil {
+		return err
 	}
 
 	ddls := []string{}
diff --git a/cmd/import.go b/cmd/import.go
index b0980f2..632701d 100644
--- a/cmd/import.go
+++ b/cmd/import.go
@@ -105,24 +105,8 @@ func completeImportConfig() (err error) {
 		ImportConfig.Data = filepath.Join(GlobalConfig.OutputDir, "gendata")
 	}
 
-	GlobalConfig.DBs, GlobalConfig.Tables = lo.Uniq(GlobalConfig.DBs), lo.Uniq(GlobalConfig.Tables)
-	dbs, tables := GlobalConfig.DBs, GlobalConfig.Tables
-	if len(dbs) == 0 && len(tables) == 0 {
-		return errors.New("expected at least one database or tables, please use --dbs/--tables flag")
-	} else if len(dbs) == 1 {
-		// prepend default database if only one database specified
-		prefix := dbs[0] + "."
-		for i, t := range GlobalConfig.Tables {
-			if !strings.Contains(t, ".") {
-				GlobalConfig.Tables[i] = prefix + t
-			}
-		}
-	} else {
-		for _, t := range tables {
-			if !strings.Contains(t, ".") {
-				return errors.New("expected database in table name when zero/multiple databases specified, e.g. --tables db1.table1,db2.table2")
-			}
-		}
+	if err := completeDBTables("expected at least one database or tables, please use --dbs/--tables flag"); err != nil {
+		return err
 	}
 
 	table2datafiles := map[string][]string{}
diff --git a/cmd/root.go b/cmd/root.go
index ddc4bb4..9cd9797 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -16,21 +16,29 @@ limitations under the License.
 package cmd
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"reflect"
 	"runtime"
 	"strings"
+	"sync/atomic"
 
+	"github.com/jmoiron/sqlx"
+	"github.com/samber/lo"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
+
+	"github.com/Thearas/dodo/src"
 )
 
 var (
 	GlobalConfig    = Global{}
 	DefaultParallel = 10
+
+	completionDB *sqlx.DB
 )
 
 type Global struct {
@@ -88,10 +96,7 @@ func init() {
 	rootCmd.PersistentFlags().SortFlags = false
 	rootCmd.Flags().SortFlags = false
 
-	parallel := runtime.NumCPU()
-	if parallel > DefaultParallel {
-		parallel = DefaultParallel
-	}
+	parallel := min(runtime.NumCPU(), DefaultParallel)
 
 	pFlags := rootCmd.PersistentFlags()
 	pFlags.StringVarP(&GlobalConfig.ConfigFile, "config", "C", "", "Config file (default is $HOME/.dodo.yaml)")
@@ -109,10 +114,77 @@ func init() {
 	pFlags.StringVar(&GlobalConfig.Catalog, "catalog", "", "Catalog to work on")
 	pFlags.StringSliceVarP(&GlobalConfig.DBs, "dbs", "D", []string{}, "DBs to work on")
 	pFlags.StringSliceVarP(&GlobalConfig.Tables, "tables", "T", []string{}, "Tables to work on")
+
+	compInit := func(cmd *cobra.Command) error {
+		if err := initConfig(cmd); err != nil {
+			return err
+		}
+		db := setupCompletionDB()
+		if db == nil {
+			return errors.New("failed to connect to database for completion")
+		}
+		return nil
+	}
+	compopts := cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveDefault | cobra.ShellCompDirectiveKeepOrder
+
+	rootCmd.RegisterFlagCompletionFunc("catalog", func(cmd *cobra.Command, _ []string, tocomplete string) ([]string, cobra.ShellCompDirective) {
+		if err := compInit(cmd); err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+		items, err := src.ShowCatalogs(cmd.Context(), completionDB, tocomplete)
+		if len(items) == 0 || err != nil {
+			return []string{"No catalog found"}, cobra.ShellCompDirectiveError
+		}
+		return items, compopts
+	})
+
+	rootCmd.RegisterFlagCompletionFunc("dbs", func(cmd *cobra.Command, _ []string, tocomplete string) ([]string, cobra.ShellCompDirective) {
+		if err := compInit(cmd); err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+		items, err := src.ShowDatabases(cmd.Context(), completionDB, tocomplete)
+		if len(items) == 0 || err != nil {
+			return []string{"No database found"}, cobra.ShellCompDirectiveError
+		}
+		return items, compopts
+	})
+
+	rootCmd.RegisterFlagCompletionFunc("tables", func(cmd *cobra.Command, _ []string, tocomplete string) ([]string, cobra.ShellCompDirective) {
+		if err := compInit(cmd); err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+
+		var dbname string
+		dbtable := strings.SplitN(tocomplete, ".", 2)
+		if len(dbtable) == 2 {
+			dbname = dbtable[0]
+			tocomplete = dbtable[1]
+		} else if len(GlobalConfig.DBs) == 0 {
+			dbCompF, _ := rootCmd.GetFlagCompletionFunc("dbs")
+			items, compopts := dbCompF(cmd, nil, tocomplete)
+			return lo.Map(items, func(item string, _ int) string { return item + "." }), compopts
+		} else if len(GlobalConfig.DBs) == 1 {
+			dbname = GlobalConfig.DBs[0]
+		} else {
+			return lo.Map(GlobalConfig.DBs, func(db string, _ int) string { return db + "." }), compopts
+		}
+
+		items, err := src.ShowTables(cmd.Context(), completionDB, dbname, tocomplete)
+		if len(items) == 0 || err != nil {
+			return []string{"No table found"}, cobra.ShellCompDirectiveError
+		}
+		return lo.Map(items, func(item *src.Schema, _ int) string { return dbname + "." + item.Name }), compopts
+	})
 }
 
+var isCfgInited atomic.Bool
+
 // initConfig reads in config file and ENV variables if set.
 func initConfig(cmd *cobra.Command, prefixs ...string) error {
+	if isCfgInited.Swap(true) {
+		return nil
+	}
+
 	cfgFile := GlobalConfig.ConfigFile
 	if cfgFile != "" {
 		// Use config file from the flag.
@@ -195,3 +267,42 @@ func initLog() error {
 	logrus.SetFormatter(&logrus.TextFormatter{})
 	return nil
 }
+
+func completeDBTables(dbtableNotFoundErr ...string) error {
+	GlobalConfig.DBs, GlobalConfig.Tables = lo.Uniq(GlobalConfig.DBs), lo.Uniq(GlobalConfig.Tables)
+	dbs, tables := GlobalConfig.DBs, GlobalConfig.Tables
+	if len(dbs) == 0 && len(tables) == 0 {
+		if len(dbtableNotFoundErr) > 0 {
+			return errors.New(dbtableNotFoundErr[0])
+		}
+		return errors.New("expected at least one database or tables, please use --dbs/--tables flag or --ddl flag with '.sql' file(s)")
+	} else if len(dbs) == 1 {
+		// prepend default database if only one database specified
+		prefix := dbs[0] + "."
+		for i, t := range GlobalConfig.Tables {
+			if !strings.Contains(t, ".") {
+				GlobalConfig.Tables[i] = prefix + t
+			}
+		}
+	} else {
+		for _, t := range tables {
+			if !strings.Contains(t, ".") {
+				return errors.New("expected database in table name when zero/multiple databases specified, e.g. --tables db1.table1,db2.table2")
+			}
+		}
+	}
+	return nil
+}
+
+func setupCompletionDB() *sqlx.DB {
+	if completionDB != nil {
+		return completionDB
+	}
+
+	db, err := connectDBWithoutDBName()
+	if err != nil {
+		return nil
+	}
+	completionDB = db
+	return db
+}
diff --git a/go.mod b/go.mod
index 6ee5428..3edb66e 100644
--- a/go.mod
+++ b/go.mod
@@ -17,7 +17,7 @@ require (
 	github.com/jmoiron/sqlx v1.3.5
 	github.com/manifoldco/promptui v0.9.0
 	github.com/openai/openai-go v1.7.0
-	github.com/samber/lo v1.49.1
+	github.com/samber/lo v1.51.0
 	github.com/sirupsen/logrus v1.9.3
 	github.com/spf13/cast v1.6.0
 	github.com/spf13/cobra v1.8.1
@@ -29,8 +29,8 @@ require (
 	github.com/zeebo/blake3 v0.2.4
 	golang.org/x/crypto v0.35.0
 	golang.org/x/exp v0.0.0-20240823005443-9b4947da3948
-	golang.org/x/sync v0.11.0
-	golang.org/x/text v0.22.0
+	golang.org/x/sync v0.16.0
+	golang.org/x/text v0.27.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
diff --git a/go.sum b/go.sum
index 8cc3e0c..04af59d 100644
--- a/go.sum
+++ b/go.sum
@@ -68,8 +68,6 @@ github.com/mattn/go-sqlite3 v1.14.6 h1:dNPt6NO46WmLVt2DLNpwczCmdV5boIZ6g/tlDrlRU
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
-github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
-github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/openai/openai-go v1.7.0 h1:M1JfDjQgo3d3PsLyZgpGUG0wUAaUAitqJPM4Rl56dCA=
 github.com/openai/openai-go v1.7.0/go.mod h1:g461MYGXEXBVdV5SaR/5tNzNbSfwTBBefwc+LlDCK0Y=
 github.com/pelletier/go-toml/v2 v2.2.2 h1:aYUidT7k73Pcl9nb2gScu7NSrKCSHIDE89b3+6Wq+LM=
@@ -84,8 +82,8 @@ github.com/sagikazarmark/locafero v0.4.0 h1:HApY1R9zGo4DBgr7dqsTH/JJxLTTsOt7u6ke
 github.com/sagikazarmark/locafero v0.4.0/go.mod h1:Pe1W6UlPYUk/+wc/6KFhbORCfqzgYEpgQ3O5fPuL3H4=
 github.com/sagikazarmark/slog-shim v0.1.0 h1:diDBnUNK9N/354PgrxMywXnAwEr1QZcOr6gto+ugjYE=
 github.com/sagikazarmark/slog-shim v0.1.0/go.mod h1:SrcSrq8aKtyuqEI1uvTDTK1arOWRIczQRv+GVI1AkeQ=
-github.com/samber/lo v1.49.1 h1:4BIFyVfuQSEpluc7Fua+j1NolZHiEHEpaSEKdsH0tew=
-github.com/samber/lo v1.49.1/go.mod h1:dO6KHFzUKXgP8LDhU0oI8d2hekjXnGOu0DB8Jecxd6o=
+github.com/samber/lo v1.51.0 h1:kysRYLbHy/MB7kQZf5DSN50JHmMsNEdeY24VzJFu7wI=
+github.com/samber/lo v1.51.0/go.mod h1:4+MXEGsJzbKGaUEQFKBq2xtfuznW9oz/WrgyzMzRoM0=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/smartystreets/assertions v1.13.1 h1:Ef7KhSmjZcK6AVf9YbJdvPYG9avaF0ZxudX+ThRdWfU=
@@ -145,8 +143,8 @@ golang.org/x/crypto v0.35.0 h1:b15kiHdrGCHrP6LvwaQ3c03kgNhhiMgvlhxHQhmg2Xs=
 golang.org/x/crypto v0.35.0/go.mod h1:dy7dXNW32cAb/6/PRuTNsix8T+vJAqvuIy5Bli/x0YQ=
 golang.org/x/exp v0.0.0-20240823005443-9b4947da3948 h1:kx6Ds3MlpiUHKj7syVnbp57++8WpuKPcR5yjLBjvLEA=
 golang.org/x/exp v0.0.0-20240823005443-9b4947da3948/go.mod h1:akd2r19cwCdwSwWeIdzYQGa/EZZyqcOdwWiwj5L5eKQ=
-golang.org/x/sync v0.11.0 h1:GGz8+XQP4FvTTrjZPzNKTMFtSXH80RAzG+5ghFPgK9w=
-golang.org/x/sync v0.11.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
+golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -155,11 +153,11 @@ golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
 golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/term v0.29.0 h1:L6pJp37ocefwRRtYPKSWOWzOtWSxVajvz2ldH/xi3iU=
 golang.org/x/term v0.29.0/go.mod h1:6bl4lRlvVuDgSf3179VpIxBF0o10JUpXWOnI7nErv7s=
-golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
-golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
+golang.org/x/text v0.27.0 h1:4fGWRpyh641NLlecmyl4LOe6yDdfaYNrGb2zdfo4JV4=
+golang.org/x/text v0.27.0/go.mod h1:1D28KMCvyooCX9hBiosv5Tz/+YLxj0j7XhWjpSUF7CU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
 gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/introduction-zh.md b/introduction-zh.md
index be45da1..48ec3d5 100644
--- a/introduction-zh.md
+++ b/introduction-zh.md
@@ -28,6 +28,7 @@
   - [回放速度和并发](#回放速度和并发)
   - [其他回放参数](#其他回放参数)
 - [对比回放结果](#对比回放结果)
+- [导出表数据](#导出表数据)
 - [最佳实践](#最佳实践)
   - [命令行提示与自动补全](#命令行提示与自动补全)
   - [环境变量和配置文件](#环境变量和配置文件)
@@ -634,6 +635,22 @@ dodo replay -f output/q0.sql
 
 > `--min-duration-diff` 表示打印执行时长差异超过此值的 SQL，默认 `100ms`
 
+## 导出表数据
+
+`dodo export --help`
+
+对 [Export](https://doris.apache.org/docs/sql-manual/sql-statements/data-modification/load-and-export/EXPORT) 语句的封装，导出表数据到 `s3`、`hdfs` 或 `local` 存储。
+
+> [!NOTE]
+>
+> - 命令会等待导出跑完后返回，中途终止会取消导出
+> - CSV 格式下默认的列分隔符是 `☆`，可通过 `-p column_separator=xxx` 指定
+
+```sh
+# 导出目标 `--url` 中可使用占位符 `{db}` 和 `{table}`，分别代表数据库名和表名
+dodo export --dbs db1 --tables t1,t2 --target s3 --url 's3://bucket/export/{db}/{table}_' -p timeout=60 -w s3.endpoint=xxx -w s3.access_key=xxx -w s3.secret_key=xxx
+```
+
 ## 最佳实践
 
 ### 命令行提示与自动补全
diff --git a/introduction.md b/introduction.md
index 677fe58..b099f9e 100644
--- a/introduction.md
+++ b/introduction.md
@@ -28,6 +28,7 @@
   - [Replay Speed and Concurrency](#replay-speed-and-concurrency)
   - [Other Replay Parameters](#other-replay-parameters)
 - [Diff Replay Results](#diff-replay-results)
+- [Export table data](#export-table-data)
 - [Best Practices](#best-practices)
   - [Command-line Prompts and Autocompletion](#command-line-prompts-and-autocompletion)
   - [Environment Variables and Configuration Files](#environment-variables-and-configuration-files)
@@ -637,6 +638,22 @@ There are two ways:
 
 > `--min-duration-diff` means print SQLs whose execution duration difference exceeds this value. Default is `100ms`.
 
+## Export table data
+
+`dodo export --help`
+
+Encapsulates the [Export](https://doris.apache.org/docs/sql-manual/sql-statements/data-modification/load-and-export/EXPORT) SQL statement, exporting table data to `s3`, `hdfs` or `local` storage.
+
+> [!NOTE]
+>
+> - The command will wait for the export to complete, and the export will be canceled if the command is terminated.
+> - The column separator is `☆` by default in CSV format. You can specify them with `-p column_separator=xxx`
+
+```sh
+# The placeholders `{db}` and `{table}` can be used in the export target `--url`, representing the database name and table name respectively
+dodo export --dbs db1 --tables t1,t2 --target s3 --url 's3://bucket/export/{db}/{table}_' -p timeout=60 -w s3.endpoint=xxx -w s3.access_key=xxx -w s3.secret_key=xxx
+```
+
 ## Best Practices
 
 ### Command-line Prompts and Autocompletion
diff --git a/src/db.go b/src/db.go
index 210b6f7..a80b14c 100644
--- a/src/db.go
+++ b/src/db.go
@@ -201,6 +201,26 @@ func getStmtfromShowCreate(r *sqlx.Rows) (schema string, err error) {
 	return
 }
 
+func ShowCatalogs(ctx context.Context, conn *sqlx.DB, namePrefix string) ([]string, error) {
+	r, err := conn.QueryxContext(ctx, InternalSqlComment+`SHOW CATALOGS LIKE ?`, SanitizeLike(namePrefix)+"%")
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+
+	catalogs := []string{}
+	for r.Next() {
+		catalog := map[string]any{}
+		if err := r.MapScan(catalog); err != nil {
+			return nil, err
+		}
+		// cobra.CompDebug(fmt.Sprintln("asdadad", catalog), true)
+		catalogs = append(catalogs, cast.ToString(catalog["CatalogName"]))
+	}
+
+	return catalogs, r.Err()
+}
+
 func ShowDatabases(ctx context.Context, conn *sqlx.DB, dbnamePrefix string) ([]string, error) {
 	dbs := []string{}
 	err := conn.SelectContext(ctx, &dbs, InternalSqlComment+`SELECT SCHEMA_NAME FROM information_schema.schemata WHERE SCHEMA_NAME not in ('__internal_schema', 'information_schema', 'mysql') AND SCHEMA_NAME like ? ORDER BY SCHEMA_NAME`, SanitizeLike(dbnamePrefix)+"%")
@@ -274,6 +294,58 @@ func ShowFronendsDisksDir(ctx context.Context, conn *sqlx.DB, diskType string) (
 	return dir, r.Err()
 }
 
+func exportTable(ctx context.Context, conn *sqlx.DB, dbname, table, target, toURL string, with, props map[string]string) error {
+	strKV := func(k string, v string) string {
+		if !strings.HasPrefix(k, `"`) && !strings.HasSuffix(k, `'`) {
+			k = string(MustJsonMarshal(strings.TrimSpace(k)))
+		}
+		if !strings.HasPrefix(v, `"`) && !strings.HasSuffix(v, `'`) {
+			v = string(MustJsonMarshal(strings.TrimSpace(v)))
+		}
+		return fmt.Sprintf("  %s = %s", k, v)
+	}
+
+	stmt := fmt.Sprintf("EXPORT TABLE `%s`.`%s` TO '%s'\nPROPERTIES (\n%s\n)\nWITH %s (\n%s\n);",
+		dbname, table, toURL,
+		strings.Join(lo.MapToSlice(props, strKV), ",\n"),
+		strings.ToUpper(target),
+		strings.Join(lo.MapToSlice(with, strKV), ",\n"),
+	)
+
+	_, err := conn.ExecContext(ctx, InternalSqlComment+stmt)
+	return err
+}
+
+func showExportTable(ctx context.Context, conn *sqlx.DB, dbname string, label string) (completed bool, progress string, err error) {
+	r, err := conn.QueryxContext(ctx, InternalSqlComment+fmt.Sprintf("SHOW EXPORT FROM `%s` WHERE Label = '%s' ORDER BY CreateTime desc LIMIT 1", dbname, label))
+	if err != nil {
+		return false, "", err
+	}
+	defer r.Close()
+	if !r.Next() {
+		return false, "", fmt.Errorf("no rows returned from SHOW EXPORT, db: %s, label: %s", dbname, label)
+	}
+
+	vals := map[string]any{}
+	if err := r.MapScan(vals); err != nil {
+		return false, "", err
+	}
+
+	// https://doris.apache.org/docs/sql-manual/sql-statements/data-modification/load-and-export/SHOW-EXPORT#return-value
+	state := cast.ToString(vals["State"])
+	progress = cast.ToString(vals["Progress"])
+	errMsg := cast.ToString(vals["ErrorMsg"])
+	if state == "CANCELLED" || errMsg != "" {
+		return false, "", fmt.Errorf("export failed: %s", errMsg)
+	}
+	return state == "FINISHED", progress, nil
+}
+
+func cancelExportTable(ctx context.Context, conn *sqlx.DB, dbname string, label string) error {
+	_, err := conn.ExecContext(ctx, InternalSqlComment+fmt.Sprintf("CANCEL EXPORT FROM `%s` WHERE Label = '%s'", dbname, label))
+	return err
+}
+
 //nolint:revive
 func GetTablesStats(ctx context.Context, conn *sqlx.DB, analyze bool, dbname string, tables ...string) ([]*TableStats, error) {
 	if len(tables) == 0 {
diff --git a/src/export.go b/src/export.go
new file mode 100644
index 0000000..ae87d7f
--- /dev/null
+++ b/src/export.go
@@ -0,0 +1,80 @@
+package src
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/jmoiron/sqlx"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cast"
+
+	gen "github.com/Thearas/dodo/src/generator"
+)
+
+const (
+	ExportLabelPrefix       = "dodo_export_"
+	DefaultExportTimeoutSec = 7200
+)
+
+func Export(
+	ctx context.Context,
+	conn *sqlx.DB,
+	dbname, table, target, toURL string,
+	with, props map[string]string,
+) error {
+	label := props["label"]
+	if label == "" {
+		// label format: dodo_export_<dbname>_<table>_<random(3)>
+		label = fmt.Sprintf("%s%s_%s_%s", ExportLabelPrefix, dbname, table, gen.RandomStr(3, 3))
+	}
+
+	timeout := cast.ToInt(props["timeout"])
+	if timeout == 0 {
+		timeout = DefaultExportTimeoutSec
+	}
+
+	colSep := props["column_separator"]
+	if colSep == "" {
+		colSep = string(ColumnSeparator)
+	}
+
+	// set default properties
+	props["label"] = label
+	props["timeout"] = strconv.Itoa(timeout)
+	props["column_separator"] = colSep
+
+	// execute EXPORT statement
+	if err := exportTable(ctx, conn, dbname, table, target, toURL, with, props); err != nil {
+		return err
+	}
+
+	// wait for export to complete
+	var (
+		now     = time.Now()
+		waitSec = 5
+	)
+	for int(time.Since(now).Seconds()) <= timeout+waitSec {
+		select {
+		case <-ctx.Done():
+			// cancel export job
+			err := cancelExportTable(ctx, conn, dbname, label)
+			return errors.Join(ctx.Err(), err)
+		case <-time.After(time.Duration(waitSec) * time.Second):
+			// continue
+		}
+
+		completed, progress, err := showExportTable(ctx, conn, dbname, label)
+		if err != nil {
+			return fmt.Errorf("show export failed: %w", err)
+		}
+		if completed {
+			return nil
+		}
+		logrus.Debugf("Exporting table '%s.%s', progress: %s\n", dbname, table, progress)
+	}
+
+	return fmt.Errorf("export table '%s.%s' timed out after %d seconds", dbname, table, timeout)
+}
diff --git a/src/gendata.go b/src/gendata.go
index d5708ab..167865d 100644
--- a/src/gendata.go
+++ b/src/gendata.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/goccy/go-json"
 	"github.com/samber/lo"
 	"github.com/sirupsen/logrus"
 
@@ -69,10 +68,12 @@ func NewTableGen(ddlfile, createTableStmt string, stats *TableStats, rows int, s
 	streamLoadCols := make([]string, 0, colCount) // construct for streamload header `curl -H 'columns: xxx'`
 	hasStreamLoadColMapping := false
 	for i, col := range c.ColumnDefs().GetCols() {
-		colName := strings.Trim(col.GetColName().GetText(), "`")
-		colType_ := col.GetType_()
-		visitor := gen.NewTypeVisitor(fmt.Sprintf("%s.%s", table, colName), nil)
-		colBaseType := visitor.GetBaseType(colType_)
+		var (
+			colName     = strings.Trim(col.GetColName().GetText(), "`")
+			colType_    = col.GetType_()
+			visitor     = gen.NewTypeVisitor(fmt.Sprintf("%s.%s", table, colName), nil)
+			colBaseType = visitor.GetBaseType(colType_)
+		)
 
 		// get column gen rule
 		visitor.GenRule = newColGenRule(col, colName, colBaseType, colStats, customColumnRule)
@@ -84,25 +85,10 @@ func NewTableGen(ddlfile, createTableStmt string, stats *TableStats, rows int, s
 		tg.Columns = append(tg.Columns, colName)
 
 		// column mapping in streamload header
-		var loadMapping string
-		loadCol := colName
-		if len(streamloadColNames) > 0 {
-			loadCol = streamloadColNames[i]
-		}
-		switch colBaseType {
-		case "BITMAP":
-			hasStreamLoadColMapping = true
-			loadMapping = fmt.Sprintf("raw_%s,`%s`=bitmap_from_array(cast(raw_%s as ARRAY<BIGINT(20)>))", loadCol, loadCol, loadCol)
-		case "HLL":
-			hasStreamLoadColMapping = true
-			loadMapping = fmt.Sprintf("raw_%s,`%s`=hll_empty()", loadCol, loadCol)
-			if from := visitor.GetRule("from"); from != nil {
-				loadMapping = fmt.Sprintf("raw_%s,`%s`=hll_hash(%v)", loadCol, loadCol, from)
-			}
-		default:
-			loadMapping = "`" + loadCol + "`"
-		}
-		streamLoadCols = append(streamLoadCols, loadMapping)
+		loadCol := lo.NthOr(streamloadColNames, i, colName)
+		mapping, needMapping := buildStreamLoadMapping(visitor, loadCol, colBaseType)
+		streamLoadCols = append(streamLoadCols, mapping)
+		hasStreamLoadColMapping = hasStreamLoadColMapping || needMapping
 	}
 
 	if hasStreamLoadColMapping {
@@ -112,7 +98,12 @@ func NewTableGen(ddlfile, createTableStmt string, stats *TableStats, rows int, s
 	return tg, nil
 }
 
-func newColGenRule(col parser.IColumnDefContext, colName, colType string, colStats map[string]*ColumnStats, customColumnRule map[string]GenRule) GenRule {
+func newColGenRule(
+	col parser.IColumnDefContext,
+	colName, colBaseType string,
+	colStats map[string]*ColumnStats,
+	customColumnRule map[string]GenRule,
+) GenRule {
 	genRule := GenRule{}
 
 	// 1. Merge rules in stats
@@ -125,15 +116,21 @@ func newColGenRule(col parser.IColumnDefContext, colName, colType string, colSta
 			genRule["null_frequency"] = nullFreq
 		}
 
-		if IsStringType(colType) {
+		if IsStringType(colBaseType) {
 			avgLen := colstats.AvgSizeByte
 			genRule["length"] = avgLen
 
-			// HACK: +-5 on string avg size as length
-			if avgLen > 5 && colType != "CHAR" {
+			// HACK: +-5/10 on string avg size as length
+			if colBaseType != "CHAR" && len(colstats.Min) != len(colstats.Max) {
+				var extent int64
+				if avgLen > 10 {
+					extent = 10
+				} else if avgLen > 5 {
+					extent = 5
+				}
 				genRule["length"] = GenRule{
-					"min": avgLen - 5,
-					"max": avgLen + 5,
+					"min": avgLen - extent,
+					"max": avgLen + extent,
 				}
 			}
 		} else {
@@ -161,6 +158,27 @@ func newColGenRule(col parser.IColumnDefContext, colName, colType string, colSta
 	return genRule
 }
 
+func buildStreamLoadMapping(visitor *gen.TypeVisitor, loadColName, colBaseType string) (string, bool) {
+	var (
+		mapping     string
+		needMapping bool
+	)
+	switch colBaseType {
+	case "BITMAP":
+		needMapping = true
+		mapping = fmt.Sprintf("raw_%s,`%s`=bitmap_from_array(cast(raw_%s as ARRAY<BIGINT(20)>))", loadColName, loadColName, loadColName)
+	case "HLL":
+		needMapping = true
+		mapping = fmt.Sprintf("raw_%s,`%s`=hll_empty()", loadColName, loadColName)
+		if from := visitor.GetRule("from"); from != nil {
+			mapping = fmt.Sprintf("raw_%s,`%s`=hll_hash(%v)", loadColName, loadColName, from)
+		}
+	default:
+		mapping = "`" + loadColName + "`"
+	}
+	return mapping, needMapping
+}
+
 type TableGen struct {
 	Name       string
 	Columns    []string
@@ -215,15 +233,7 @@ func (tg *TableGen) genOne(w *bufio.Writer, colIdxRefGens map[int]*gen.RefGen) {
 			}
 		}
 
-		if val == nil {
-			w.WriteString(`\N`)
-		} else if v, ok := val.(json.RawMessage); ok {
-			w.Write(v)
-		} else if s, ok := val.(string); ok {
-			w.WriteString(s)
-		} else {
-			fmt.Fprint(w, val)
-		}
+		gen.WriteColVal(w, val)
 		if i != len(tg.colGens)-1 {
 			w.WriteRune(ColumnSeparator)
 		}
diff --git a/src/generator/format.go b/src/generator/format.go
index 6bf9c5c..34b0984 100644
--- a/src/generator/format.go
+++ b/src/generator/format.go
@@ -58,12 +58,7 @@ func (g *FormatGen) Gen() any {
 		}
 
 		result := tagF.Call(nil)[0].Interface()
-		if result == nil {
-			return w.Write([]byte(`\N`))
-		} else if s, ok := result.(string); ok {
-			return w.Write([]byte(s))
-		}
-		return w.Write(fmt.Append(nil, result))
+		return WriteColVal(w.(ColValWriter), result)
 	})
 	if err != nil {
 		logrus.Errorf("format execute templace failed, err: %v\n", err)
diff --git a/src/generator/generator.go b/src/generator/generator.go
index 8ba5eeb..7e02db5 100644
--- a/src/generator/generator.go
+++ b/src/generator/generator.go
@@ -63,47 +63,24 @@ func NewTypeVisitor(colpath string, genRule GenRule) *TypeVisitor {
 }
 
 func (v *TypeVisitor) GetGen(type_ parser.IDataTypeContext) Gen {
-	baseType := v.GetBaseType(type_)
-	v.MergeDefaultRule(baseType) // Merge global (aka. default) generation rules.
+	var (
+		g        Gen
+		err      error
+		baseType = v.GetBaseType(type_)
+	)
+
+	// Merge global (aka. default) generation rules.
+	v.MergeDefaultRule(baseType)
 	if logrus.GetLevel() > logrus.DebugLevel {
 		logrus.Tracef("gen rule of '%s': %s\n", v.Colpath, string(MustJSONMarshal(v.GenRule)))
 	}
 
-	var (
-		g   Gen
-		err error
-	)
-
-	// 1. custom generator
 	if customGenRule, ok := v.GetRule("gen").(GenRule); ok {
-		var (
-			g_      Gen
-			genName string
-		)
-		for name, newCustomGen := range CustomGenConstructors {
-			if _, ok := customGenRule[name]; !ok {
-				continue
-			}
-			if g_ != nil {
-				logrus.Fatalf("Multiple custom generators found for column '%s', only one is allowed, but got both: %s and %s\n", v.Colpath, genName, name)
-			}
-
-			g_, err = newCustomGen(v, type_, customGenRule)
-			if err != nil {
-				logrus.Fatalf("Invalid custom generator '%s' for column '%s', err: %v\n", name, v.Colpath, err)
-			}
-			genName = name
-		}
-		g = g_
-		if g == nil {
-			logrus.Fatalf("Custom generator not found for column '%s', expect one of %v\n",
-				v.Colpath,
-				lo.MapToSlice(CustomGenConstructors, func(name string, _ CustomGenConstructor) string { return name }),
-			)
-		}
+		// 1. custom generator
+		g = v.getCustomGen(type_, customGenRule)
 	} else {
 		// 2. type generator
-		g = v.getTypeGen(baseType, type_)
+		g = v.getTypeGen(type_, baseType)
 	}
 
 	// format generator
@@ -130,7 +107,36 @@ func (v *TypeVisitor) GetGen(type_ parser.IDataTypeContext) Gen {
 	return g
 }
 
-func (v *TypeVisitor) getTypeGen(baseType string, type_ parser.IDataTypeContext) Gen {
+func (v *TypeVisitor) getCustomGen(type_ parser.IDataTypeContext, customGenRule GenRule) Gen {
+	var (
+		g       Gen
+		genName string
+		err     error
+	)
+	for name, newCustomGen := range CustomGenConstructors {
+		if _, ok := customGenRule[name]; !ok {
+			continue
+		}
+		if g != nil {
+			logrus.Fatalf("Multiple custom generators found for column '%s', only one is allowed, but got both: %s and %s\n", v.Colpath, genName, name)
+		}
+
+		g, err = newCustomGen(v, type_, customGenRule)
+		if err != nil {
+			logrus.Fatalf("Invalid custom generator '%s' for column '%s', err: %v\n", name, v.Colpath, err)
+		}
+		genName = name
+	}
+	if g == nil {
+		logrus.Fatalf("Custom generator not found for column '%s', expect one of %v\n",
+			v.Colpath,
+			lo.MapToSlice(CustomGenConstructors, func(name string, _ CustomGenConstructor) string { return name }),
+		)
+	}
+	return g
+}
+
+func (v *TypeVisitor) getTypeGen(type_ parser.IDataTypeContext, baseType string) Gen {
 	var g Gen
 	switch ty := type_.(type) {
 	case *parser.ComplexDataTypeContext:
@@ -212,7 +218,7 @@ func (v *TypeVisitor) getTypeGen(baseType string, type_ parser.IDataTypeContext)
 				genRule = maps.Clone(v.GenRule)
 				delete(genRule, "structure")
 			} else {
-				logrus.Fatalf("JSON/JSONB/VARIANT must have gen rule 'structure' at column '%s'\n", v.Colpath)
+				logrus.Fatalf("JSON/JSONB/VARIANT must have gen rule 'structure' or 'gen' at column '%s'\n", v.Colpath)
 			}
 
 			p := parser.NewParser(v.Colpath, structure)
diff --git a/src/generator/misc.go b/src/generator/misc.go
index ad2803e..c8bd471 100644
--- a/src/generator/misc.go
+++ b/src/generator/misc.go
@@ -2,6 +2,7 @@ package generator
 
 import (
 	"fmt"
+	"io"
 	"math/rand/v2"
 	"time"
 	"unsafe"
@@ -14,6 +15,28 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+type ColValWriter interface {
+	io.Writer
+	io.StringWriter
+}
+
+func WriteColVal(w ColValWriter, val any) (int, error) {
+	if val == nil {
+		return w.WriteString(`\N`)
+	}
+
+	switch v := val.(type) {
+	case string:
+		return w.WriteString(v)
+	case json.RawMessage:
+		return w.Write(v)
+	case []byte:
+		return w.Write(v)
+	default:
+		return fmt.Fprint(w, val)
+	}
+}
+
 //nolint:revive
 func MergeGenRules(dst, src GenRule, overwrite bool) {
 	for k, v := range src {
diff --git a/src/prompt/gendata.xml b/src/prompt/gendata.xml
index bcd15f3..6bb598c 100644
--- a/src/prompt/gendata.xml
+++ b/src/prompt/gendata.xml
@@ -5,10 +5,11 @@ So your task is generating YAML configurations for the data generation tool dodo
 </request>
 
 <requirements>
-1. The generated data must be able to be queried by user's queries
-2. The YAML configurations should according to 'usage' below. Do not use rule key in `gendata.yaml` that haven't been documented in 'usage'
-3. When column stats conflict with queries conditions, prioritize queries conditions and ignore column stats
-4. Output should be a valid YAML and do not output anything else except YAML
+1. The generated data must be able to be inserted into the tables in user prompt, constraints like UNIQUE KEY and PARTITIONS must be satisfied
+2. The generated data must be able to be queried by user's queries
+3. The YAML configurations should according to 'usage' below. Do not use rule key in `gendata.yaml` that haven't been documented in 'usage'
+4. When column stats conflict with queries conditions, prioritize queries conditions and ignore column stats
+5. Output should be a valid YAML and do not output anything else except YAML
 </requirements>
 
 <usage>
@@ -1187,8 +1188,7 @@ tables:
         gen:
           ref: employees.employee_id
 </output>
-</examples>
-
+</example>
 </examples>
 
 </usage>
@@ -1199,7 +1199,7 @@ Do not generation rules for those columns that not been used as condition (like
 </tip>
 
 <tip>
-The list of generation rule `format` built-in tags (placeholder like {{month}}) in Markdown table:
+The list of built-in tags (placeholder like {{month}}) for generation rule `format` in Markdown table:
 
 
 | Name | Return Type |
diff --git a/src/prompt/gendata.xml.tpl b/src/prompt/gendata.xml.tpl
index 7914236..ddad318 100644
--- a/src/prompt/gendata.xml.tpl
+++ b/src/prompt/gendata.xml.tpl
@@ -5,10 +5,11 @@ So your task is generating YAML configurations for the data generation tool dodo
 </request>
 
 <requirements>
-1. The generated data must be able to be queried by user's queries
-2. The YAML configurations should according to 'usage' below. Do not use rule key in `gendata.yaml` that haven't been documented in 'usage'
-3. When column stats conflict with queries conditions, prioritize queries conditions and ignore column stats
-4. Output should be a valid YAML and do not output anything else except YAML
+1. The generated data must be able to be inserted into the tables in user prompt, constraints like UNIQUE KEY and PARTITIONS must be satisfied
+2. The generated data must be able to be queried by user's queries
+3. The YAML configurations should according to 'usage' below. Do not use rule key in `gendata.yaml` that haven't been documented in 'usage'
+4. When column stats conflict with queries conditions, prioritize queries conditions and ignore column stats
+5. Output should be a valid YAML and do not output anything else except YAML
 </requirements>
 
 <usage>
@@ -121,8 +122,7 @@ All kinds of generation rules example(without queries):
 <output>
 「example」
 </output>
-</examples>
-
+</example>
 </examples>
 
 </usage>
@@ -133,7 +133,7 @@ Do not generation rules for those columns that not been used as condition (like
 </tip>
 
 <tip>
-The list of generation rule `format` built-in tags (placeholder like {{month}}) in Markdown table:
+The list of built-in tags (placeholder like {{month}}) for generation rule `format` in Markdown table:
 
 「format-tags」
 </tip>